Deadly blast strikes Beirut Hezbollah stronghold

At least 22 people were killed and hundreds wounded after a powerful explosion tore through a Hezbollah bastion in southern Beirut on Thursday. A group, believed to be a rebel Syrian cell, has claimed responsibility for the attack.

A powerful explosion struck the southern Beirut stronghold of Lebanon's militant Hezbollah group on Thursday, killing at least 22 people, wounding more than 200 and trapping many others inside damaged buildings, witnesses and emergency officials said.

Residents of southern Beirut say Hezbollah, backed by Iran and Syria, was on high alert and stepped up security in the area after warnings from Syria rebels of possible retaliation for the group's support for President Bashar al-Assad.

It was not immediately known whether the explosion targeted any Hezbollah figure but it took place in a crowded residential area.

"I don't know what happened. It's as if we were struck by an earthquake," one young man at the scene told Reuters, bleeding from a wound to his stomach.

An online video surfaced shortly after the attack showing three masked men, two of them holding rifles, in front of a white flag inscribed with the Islamic profession of faith.

"You, the pig Hassan Nasrallah, we send you our second powerful message because you haven't understood yet," said one member of the group calling itself the Battalion of Aisha, the Prophet Mohammed's favourite wife.

Another little-known Syrian rebel group, the Special Forces 313 Brigade, claimed that attack and said it was in revenge for Hezbollah fighting alongside the Assad regime. The mainstream rebel Free Syrian Army condemned the action.

At the heart of the site, where fires still raged almost an hour after the blast, the twisted remains of a large van could be seen and some witnesses said they believed the explosion was caused by a car bomb.

Many cars were damaged in the explosion and the blast sent a column of black smoke over the densely populated area. The facades of several residential buildings were damaged. Charred bodies were seen inside cars caught in the explosion.

Al Mayadeen television said some people were still trapped inside apartments at the scene, close to the Sayyed al-Shuhadaa (Martyrs) complex, where Hezbollah leader Sayyed Hassan Nasrallah often addresses his followers.

Hezbollah supporters immediately put up a security cordon around the area, witnesses said.

Huge explosion

"I heard a huge explosion. It threw me several metres," said a woman in her 50s who said she had been talking to her brother in his shop.

"I don't know what happened to my brother. I can't find him," she said, bleeding from wounds to hands and face.

ON THE GROUND

Syria's conflagration has spread to neighbouring Lebanon, where there have been outbreaks of fighting reflecting the renewed sectarian tension now spreading through the Middle East.

Lebanon's Sunni Muslims mostly support the rebels in Syria, while Shi'ites have largely supported Assad, who is part of the minority Alawite sect, an offshoot of Shi'ite Islam.

Hezbollah leader Nasrallah has promised that his group will continue fighting for Assad after it spearheaded the recapture of the strategic town of Qusair in June.

There have been two attacks in southern Beirut this year. Two months before the July 9 car bomb, two rockets were fired into the area.

In October last year, a car bomb in the east of the capital killed a senior intelligence official, Wissam al-Hassan, who was close to the country's leading Sunni opposition party, which has supported the uprising in Syria.